Open-Source CAD Tools?

curtS asks: "Oregon, though with a significant technology industry, continues to use pencil and drawing board in most high school drafting classes. This does little to assist students in career preparation, whether they're interested in drawing PCBs or kitchen cabinets. Not surprisingly, a central issue is cost. High-performance hardware is, thanks to AMD, becoming more available, but what about software? Are there open-source tools out there that can help? Any experiences in other locales?" Would anyone familiar with any Open Source CAD packages care to comment on their experiences? In what area do the open source packages need to improve (if any) to bring them up to par with the functionality of their commercial counterparts?